serial driver cleanups v2

[Enrico Weigelt, metux IT consult]

Hello folks,


here's v2 of my serial cleanups queue - part I:

essentially using helpers to code more compact and switching to
devm_*() functions for mmio management.

Part II will be about moving the mmio range from mapbase and
mapsize (which are used quite inconsistently) to a struct resource
and using helpers for that. But this one isn't finished yet.
(if somebody likes to have a look at it, I can send it, too)


happy hacking


--mtx